Removed builds for nvidia unless manually triggered, and build weekly for base image

.github/workflows/build-nvidia.yml

@@ -1,20 +1,6 @@
 name: bluebuild-nvidia
 on:
-  schedule:
-    - cron:
-        "00 06 * * *" # build at 06:00 UTC every day
-        # (20 minutes after last ublue images start building)
-  push:
-    branches:
-      - main
-    paths-ignore: # don't rebuild if only documentation has changed
-      - "**.md"
-  pull_request:
   workflow_dispatch: # allow manually triggering builds
-concurrency:
-  # only run one build at a time
-  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
-  cancel-in-progress: true
 jobs:
   bluebuild:
     name: Build Custom Image

.github/workflows/build.yml

@@ -2,7 +2,7 @@ name: bluebuild
 on:
   schedule:
     - cron:
-        "00 06 * * *" # build at 06:00 UTC every day
+        "00 06 * * 1" # build at 06:00 UTC every Monday
         # (20 minutes after last ublue images start building)
   push:
     branches:
@@ -15,10 +15,6 @@ on:
       - "recipes/recipe_nvidia.yml"
   pull_request:
   workflow_dispatch: # allow manually triggering builds
-concurrency:
-  # only run one build at a time
-  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
-  cancel-in-progress: true
 jobs:
   bluebuild:
     name: Build Custom Image